From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: AW: VirtualBox 4.2.4 freezes PC using RT_PREEMPT kernel Date: Fri, 21 Dec 2012 10:13:01 -0500 Message-ID: <1356102781.5896.107.camel@gandalf.local.home> References: <1356101745.5896.102.camel@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 7bit Cc: "Koehrer Mathias (ETAS/ESS2)" , Jan Kiszka , "linux-rt-users@vger.kernel.org" To: Thomas Gleixner Return-path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:30802 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751264Ab2LUPND (ORCPT ); Fri, 21 Dec 2012 10:13:03 -0500 In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org List-ID: On Fri, 2012-12-21 at 16:05 +0100, Thomas Gleixner wrote: > On Fri, 21 Dec 2012, Steven Rostedt wrote: > > On Fri, 2012-12-21 at 08:23 +0000, Koehrer Mathias (ETAS/ESS2) wrote: > > > *** DEADLOCK *** > > > > So this is an obvious bug in virtualbox. No need to send us a config. > > This bug has nothing to do with RT. It's just that RT can expose bugs in > > mainline (or anything added to mainline) much easier. > > > > Funny thing is, this deadlock isn't even possible in RT, so there's > > probably many more bugs in the virtualbox driver. > > It's worse on RT, because that's a smp function call interrupt. Which > just cannot work on RT with the lock not being a raw lock. > Ah, I just figured it was an normal interrupt thread. I was avoiding eye cancer by not looking at the code. I guess I could have figured it out with looking at the rest of the lockdep dump, but was too lazy ;-) -- Steve